Oprah Winfrey used her talkshow tactic of springing surprises on her audiences at the weekend, when she told 73 girls who had turned up for an interview that they had been selected for a new school she is building in South Africa.

Winfrey has been working for six years on creating the school for disadvantaged girls. "I grew up with my grandmother. We had almost nothing, but my grandmother believed I had to give back what I received," she said.

"This is so exciting for me, for the girls and for their families. South Africa is like my second home and I want to give something here. I feel this project is blessed."

The Oprah Winfrey Leadership Academy for Girls, which will open next January, is estimated to have cost more than £15m and will eventually have 450 students.

Built on nine hectares (22 acres) in Meyerton, south of Johannesburg, it will offer training in leadership skills as well as traditional academic subjects. Winfrey said the academy would prepare its students to attend the "best universities in the world".

"They will grow up to help their families and communities," she added.

Winfrey personally interviewed many of the more than 3,000 girls, aged 11 and 12, who applied for places at the new school. She said she was looking for students who had done well at school, came from disadvantaged backgrounds and showed some "spark" of leadership.

Buhle Zulu, 11, thought she was attending another interview for the school when Winfrey announced that she had won a place.

"It's like I am daydreaming," the Soweto primary school pupil told the Pretoria News. "They wanted someone like me who is not shy - and I talk too much!" Winfrey hugged Buhle and told the assembled audience: "When I asked her why she wanted to come to the academy, she said: 'It's my tomorrow.'"

Buhle lives with her mother and grandmother in a small house with nine other family members. Her mother, Zanele, said: "They were looking for clever children who are disadvantaged. Buhle is a different child.

"She reads newspapers and magazines and is curious. She is always asking questions. Sometimes I have to go to the internet cafe for answers."

South African educators have welcomed the new school, saying it will give a much-needed boost to the struggling township education system.